1. Field of the Invention
The invention relates to a tool fixing device in a tool holder in whose receptacle a shaft of the tool is clamped.
2. Description of the Related Art
In known tool fixing devices (FIG. 2) a shaft 4 of a tool 1 is clamped rigidly in a receptacle 3 of a tool holder 2 by means of a clamping member 9 seated in the tool holder 2. Slim tools, for example, end milling cutters or boring bars, often produce vibration amplitudes during machining because of their minimal flexural strength and system damping action which vibration amplitudes in most cases occur in the form of a regenerative chatter. These vibrations can only be avoided by reducing the cutting depth of the tool. Slim end milling cutters are, for example, used for milling pockets, for milling deep-drawing and forging tools as well as for producing integral components for aircraft construction. The load or performance limit is the chatter tendency of the tool as a result of its minimally damped bending vibration.
However, boring operations with boring bars having a length/diameter ratio  greater than 4 are also limited in regard to their efficiency as a result of their chatter tendency. This holds true for stationary drilling tools on turning machines as well as for rotating boring tools on horizontal boring mills and milling machines.
The invention has the object to design the fixing device of the aforementioned kind such that the chatter vibrations during machining of a workpiece can be prevented without reducing the load or efficiency limits of the tool.
In accordance with the invention, this object is solved for the fixing device of the aforementioned kind in that in the force flow between the tool and the tool holder at least one static flexible element is inserted which has a high damping action.
In the fixing device according to the invention at least one static flexible element which has a high damping action is inserted into the force flow between the tool and the tool holder. As a result of this damped clamping action, the tool can yield in a springy way relative to the tool holder. As a result of the high damping action, the tool does not chatter even when it has a great length and/or is very slim. The corresponding damping element is mounted at the location of greatest relative movement between the shaft end of the tool and the tool holder. As a result of the fixing device according to the invention, the tool shaft can perform a tilting movement about its clamping location which serves as a pivot point.
Further features of the invention result from, the description and the drawings.